Earthquake Hazards & Prediction

These flashcards cover key terms and definitions related to earthquake hazards and prediction, helping to reinforce understanding of the concepts discussed in class.

Seismicity

The frequency or intensity of earthquakes experienced over a period of time in a particular area.

Focal Mechanisms

The description of the orientation and movement along a fault that produces an earthquake.

Normal Faults

A type of fault where the crust is extended and one block of rock moves down relative to another.

Strike-slip Faults

A fault on which the movement is primarily horizontal, with blocks sliding past each other.

Subduction Zones

Regions of the Earth's crust that are formed when one tectonic plate moves under another.

Liquefaction

A phenomenon where saturated soil substantially loses strength and stiffness in response to applied stress.

Epicenter

The point on the Earth's surface directly above where an earthquake originates.

Magnitude

A measure of the size of an earthquake, often expressed on the Richter scale.

Tsunamis

Large ocean waves generated when an earthquake causes a sudden vertical displacement of the sea floor.

P Waves

Primary waves or compressional waves that are the first to be detected by seismographs during an earthquake.

S Waves

Secondary waves or shear waves that arrive after P waves and cause significant ground movement.

Love Waves

Surface waves that produce horizontal shaking of the ground and are responsible for most earthquake damage.

Rayleigh Waves

Surface waves that cause the ground to lift and fall in a rolling motion, similar to ocean waves.

Ground Shaking

The shaking of the ground caused by seismic waves during an earthquake.

Hazard Assessment

The process of identifying potential hazards and assessing their risk to human life and property.

Seismic Gaps

Segments of active faults that have not experienced significant earthquake activity for a period of time.

Intraplate Earthquakes

Earthquakes that occur within tectonic plates rather than at the boundaries.

Foreshocks

Smaller earthquakes that occur in the same area as a larger earthquake in the days to weeks before it.

Aftershocks

Smaller earthquakes that occur after a major earthquake, typically decreasing in frequency and magnitude.

Earthquake Prediction

Efforts made to forecast the time, location, and magnitude of future earthquakes.

Tectonic Plates

Large slabs of the Earth's lithosphere that move over the asthenosphere, causing geological activity.

Compression

A stress that pushes rocks together, often leading to thrust faults and earthquakes.